1. Field of the Invention
The present invention relates to optical telemetry systems and, more particularly, to a method and apparatus for interrogating a distributed undersea optical acoustic surveillance system to discriminate data received from a plurality of spaced apart acoustic sensing nodes.
2. Description of the Related Art
Current undersea acoustic surveillance systems employ complicated data node assemblies to accumulate local acoustic data and time division multiplex (TDM) data onto an optical transmission medium such, for example, as a fiber-optic cable or bundle of cables. Complex circuits including lasers that consume significant amounts of power are required in each sensing node and significantly increase installation and repair costs and adversely affect reliability. In addition, the relatively low data rate of the nodes must typically be raised to a system buss rate which is in the range of 150 Mbps.